I am looking to add a second TT15 for flank collar to my dog's neck collar setup...Has anyone ever set this up so you can operate both collars for example: neck collar is left button, flank collar right button or vice/versa without switching dog to dog on the Alpha menu? I prefer to not have to run two transmitters and the price for an add on collar is about the same for some e-collars I am looking at anyways.